<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>

<style>
    .content {
        background: gray;
        display: flex;
        justify-content: center;
    } 

    .well {
        position: relative;
        width: 200px;
        height: 200px;
    }

    .well img {
        display: block;
        font-size: 0;
        width: 150px;
        height: 150px;
        border: 6px solid wheat;
        position: absolute;
        top: 0;
        left: 0;
        transition: all 2s;
    }
    .well img:nth-child(1) {
        z-index: 1;
        backface-visibility: hidden;
    }

    .well:hover img {
        transform: rotatey(180deg);
    }
</style>

<body>
    
    <div class="content">
        <div class="well">
            <img src="img/rabbit.png" alt="">
            <img src="img/nangua.jpeg" alt="">
        </div>
    </div>

</body>
</html>